<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
	</body>
</html>
<script>
	
	let obj = {
		username : 'xiaoming',
		age : 18,
		sex : '男'
	};
	
	// 使用for ... in结构
	for(let k in obj){
		
		console.log(k + ' : ' + obj[k]);
		
	}
	
	
</script>